Diagnosis of dementia by widely used screening tools and routine psychiatric or neurologic interview has error rates of up to 50%. In addition, they require highly skilled personnel for administration and often yield incomplete, unsystematic and insensitive results. In Phase I, a dual, interactive computer system was developed which is designed to speed, simplify and automate the type of comprehensive neuropsychological evaluation required for differential diagnosis of dementia. The patient's monitor incorporates a high resolution touch- sensitive monitor that allows a range of responses to be easily and immediately entered with no training or knowledge of computers. The software package includes a modular test battery consisting of six separable test modules: 1.) a branching, structured neurological interview; 2.) a standardized quantitative mental and social function status examination; 3.) a highly sensitive and specific dementia screening battery; 4.) a memory battery; 5.) visuospatial battery and 6.) a language evaluation. The dual computer design allows the test administrator to closely monitor and interact with the patient in real time via a unique, dual-interactive operating system that permits 2-way (patient<->computer) and 3-way (patient<->computer<->tester)interactions. In Phase II, significant improvements will be made by eliminating one of the computers (reducing cost and bulk and allowing portability), adding additional test modules. refining existing test modules. increasing graphics quality (adding animation) and integrating a software-controlled speech output capability to enhance communication with the patient. The successful implementation of Phase II will result in a powerful instrument for the differential diagnosis of dementia and memory testing that is suitable for clinical and research applications. Portability of the new device will allow residential testing. The validation process will be continued in Phase II at UC Irvine, Johns Hopkins and UCLA/VAMC in several pathological groups, including Senile dementia of the Alzheimer's type (SDAT) and AIDS.